The mediating role of kinesiophobia in pain intensity, physical function, and physical activity level in inflammatory arthritis.

Pain is the main symptom of inflammatory arthritis and it can impair physical functional performance and physical activity level. Some individuals can develop kinesiophobia and experience a vicious circle of worsening health. This study aimed to investigate the association between pain and physical functional performance/physical activity and determine whether kinesiophobia mediates this association. This was a cross-sectional study with individuals diagnosed with inflammatory arthritis (rheumatoid arthritis or spondyloarthritis) treated at a Rheumatology Outpatient Clinic. We assessed pain (Visual Analogue Scale), physical activity (International Physical Activity Questionnaire - long form), kinesiophobia (Tampa Scale for Kinesiophobia), and physical functional performance (Handgrip Strength Dynamometry, 30-second Sit-to-Stand test, Static Muscular Endurance test, and Timed Up and Go test). The mediating effect of kinesiophobia on the relationship between pain intensity and physical functional performance/physical activity was analyzed, and the significance of the mediating effect (kinesiophobia) was tested through a bootstrap approach. Thirty-three individuals with inflammatory arthritis (mean age: 48 ± 12 years) participated in the study. Kinesiophobia mediates the relationship between pain intensity and physical functional performance analyzed by the 30-second Sit-to-Stand test [indirect effect (IE)overall = -0.343, bootstrap 95% confidence interval (CI): -0.698 to -0.002] and by knee flexion at 90º of the dominant limb (IEoverall = -1.55, bootstrap 95% CI: -3.43 to -0.237). In conclusion, pain intensity can affect physical functional performance through kinesiophobia in individuals with inflammatory arthritis.

Exercise, mTOR Activation, and Potential Impacts on the Liver in Rodents.

The literature offers a consensus on the association between exercise training (ET) protocols based on the adequate parameters of intensity and frequency, and several adaptive alterations in the liver. Indeed, regular ET can reverse glucose and lipid metabolism disorders, especially from aerobic modalities, which can decrease intrahepatic fat formation. In terms of molecular mechanisms, the regulation of hepatic fat formation would be directly related to the modulation of the mechanistic target of rapamycin (mTOR), which would be stimulated by insulin signaling and Akt activation, from the following three different primary signaling pathways: (I) growth factor, (II) energy/ATP-sensitive, and (III) amino acid-sensitive signaling pathways, respectively. Hyperactivation of the Akt/mTORC1 pathway induces lipogenesis by regulating the action of sterol regulatory element binding protein-1 (SREBP-1). Exercise training interventions have been associated with multiple metabolic and tissue benefits. However, it is worth highlighting that the mTOR signaling in the liver in response to exercise interventions remains unclear. Hepatic adaptive alterations seem to be most outstanding when sustained by chronic interventions or high-intensity exercise protocols.

Are lower limb symmetry and self-reported symptoms associated with functional and neuromuscular outcomes in Brazilian adults with anterior cruciate ligament reconstruction? A cross-sectional study.

INTRODUCTION: After anterior cruciate ligament (ACL) reconstruction, determining readiness to return to participation is challenging. The understanding of which neuromuscular performance parameters are associated with limb symmetry and self-reported symptoms may be useful to improve monitoring the rehabilitation towards adequate decision-making to return. OBJECTIVES: To compare the ACL-operated and injury-free lower limbs regarding functional performance; and to investigate whether lower limb strength and functional performance are associated with self-reported symptoms and functional lower limb symmetry. METHOD: Thirty-four participants were included. Functional performance was assessed by using the Y-Balance test, Single-leg Hop, and Functional Movement Screen. An isokinetic dynamometer was used to evaluate the strength levels in open and closed kinetic chains. The functional lower limb symmetry was calculated considering the single-leg hop test results for each lower limb. RESULTS: There were no differences in dynamic balance (Y-Balance) between the operated and injury-free limbs. The operated limb presented a worst performance in the single-leg hop. Self-reported symptoms prevalence and lower limb symmetry were associated with knee extension strength and functional performance (Y-Balance). CONCLUSION: Individuals submitted to ACL-reconstruction presented worse functional performance in the operated limb compared to the injury-free limb. Both knee strength and dynamic balance were associated with limb symmetry and self-reported symptoms.

Analysis of high-intensity interval training on bone mineral density in an experimental model of type 2 diabetes.

PURPOSE: To analyze the effect of high-intensity interval training (HIIT) on bone mineral density (BMD) in a model of type 2 diabetes mellitus. METHODS: Thirty-two male, adult, 12-week-old rats (Rattus norvegicus), of the Wistar lineage, were used. The animals induced to the experimental model received a high fat diet for 10 days and, after that period, intraperitoneal injection of streptozotocin (40 mg·kg-1), dissolved in 20 mmol·L-1 sodium citrate solution (pH = 4.5). The experimental group of diabetes was formed by the animals that, 48 h after the injection of streptozotocin, had fasting blood glucose > 250 mg·dL-1). The animals were randomly divided into four groups with eight animals each: HIIT experimental diabetes; HIIT control; sedentary experimental diabetes and sedentary control. The animals in the HIIT group performed an aerobic exercise protocol on a treadmill inclined at an angle of 15° to the horizontal, with interspersed intensity. Five weekly sessions, lasting 49 min each, were held for 6 weeks. The analysis of cortical bone density (CBD) and BMD were performed by X-ray images using the In-Vivo Xtreme II/Bruker system. RESULTS: For CBD and BMD, when comparing diabetes and control groups, a significant difference was seen between groups in relation to HIIT (p = 0.007). Animals submitted and not submitted to HIIT in the same group showed a significant difference between groups in relation to diabetes (p < 0.001). CONCLUSIONS: The HIIT experimental diabetes group had increased CBD and BMD in comparison with the sedentary experimental diabetes group.

Cardiovascular health indicators in soccer exercise during adolescence: systematic review.

This review analyzed the studies that evaluated cardiovascular health indicators (blood pressure, waist circumference, heart rate, glucose index and lipid blood) in recreational soccer players during adolescence, and identify possible associated factors. The search was performed in the electronic databases (PubMED, SciELO, LILACS, Scopus, SPORTDiscus and Web of Science). Inclusion criteria were: population composed of children and/or adolescents (10-19 years or average age up to 19 years); studies adolescents engaged in recreational soccer regularly and observational studies with cross-sectional or longitudinal design. The process of analysis of studies involved reading titles, abstracts and full texts. After these phases, seven articles were eligible. Regarding the design, all studies were cross-sectional. Of the total studies included, five presented moderate methodological quality values and two presented low methodological quality values, according to National Heart, Lung, and Blood Institute instrument. The most cardiovascular health indicators used in recreational soccer players during adolescence was waist circumference; three studies analyzed heart rate, two evaluated blood pressure, one analyzed insulin resistance and none of the included studies analyzed lipid profile. Factors associated were analyzed in four studies, being that sedentary time and body mass index (BMI) present association with at least one indicator of cardiovascular health.

Intermittent Fasting Attenuates Exercise Training-Induced Cardiac Remodeling. / Dieta Intermitente Atenua a Remodelação Cardíaca Causada pelo Exercício Físico.

BACKGROUND: The effects of non-pharmacological interventions such as calorie restriction and exercise training on health and prevention of cardiovascular diseases have been investigated in clinical and experimental studies. OBJECTIVE: To analyze the influence of intermittent fasting and exercise training on functional fitness, glycemia and cardiac remodeling. METHODS: Wistar rats (n=60) were randomly divided into four groups: control, exercise training (ET), intermittent fasting (IF) and exercise training plus intermittent fasting (ETI). Over 12 weeks, control and ET animals were fed daily a standard commercial diet ad libitum , while IF and ETI animals were fed every other day. In addition, the ET and ETI groups were submitted to a running protocol on a treadmill. After this period, functional fitness, nutritional parameters and blood glucose levels were analyzed. In addition to heart morphology, myocardial protein expression of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) was assessed by Western-blot. The results were analyzed using two-way ANOVA and Student-Newman-Keuls test. The level of significance considered was 5%. RESULTS: Exercise training increased functional fitness in the ET and ETI groups and promoted cardiac fibrosis. The combination of intermittent fasting and exercise training resulted in a smaller area under the blood glucose curve and reduced cardiomyocyte cross-sectional area and interstitial collagen fraction in the ETI group compared to ET. ERK and JNK expression levels were similar among groups (p>0.05). CONCLUSIONS: Intermittent fasting is associated with improved glucose tolerance and attenuates cardiac remodeling induced by exercise training (Arq Bras Cardiol. 2020; 115(2):184-193).

FUNDAMENTO: A influência de intervenções não farmacológicas como restrição calórica e exercício físico sobre a saúde e prevenção de enfermidades cardíacas tem sido documentada em estudos clínicos e experimentais. OBJETIVO: Analisar a influência da combinação entre dieta intermitente e exercício físico sobre a capacidade funcional, metabolismo glicêmico e remodelação cardíaca. MÉTODOS: Foram utilizados 60 ratos Wistar machos distribuídos em quatro grupos: Controle (C), Exercício Físico (EF), Dieta Intermitente (DI) e Exercício Físico e Dieta Intermitente (EDI). Durante 12 semanas, enquanto C e EF foram tratados diariamente com dieta comercial padrão ad libitum, DI e EDI receberam dieta similar em dias alternados com dias de jejum. Os grupos EF e EDI foram submetidos a protocolo de corrida em esteira rolante. Posteriormente, foram analisadas capacidade funcional, comportamento nutricional e metabolismo glicêmico. Além da morfologia do coração, a expressão proteica das proteínas extracellular signal-regulated kinase (ERK) e c-Jun N-terminal kinase (JNK) no coração foi avaliada por Western-blot. A análise dos resultados foi feita por meio de Two-Way ANOVA e teste de Student-Newman-Keuls. O nível de significância considerado foi de 5%. RESULTADOS: O exercício físico aumentou a capacidade funcional nos grupos EF e EDI, e acarretou fibrose cardíaca. A combinação entre dieta intermitente e exercício físico resultou em menor área sob a curva de glicemia e menores medidas de área e interstício cardíaco no EDI em relação ao EF. A expressão de proteínas ERK e JNK foi similar entre os grupos (p>0,05). CONCLUSÕES: Dieta intermitente se associa com melhor tolerância glicêmica e atenua o processo de remodelação cardíaca decorrente do exercício físico. (Arq Bras Cardiol. 2020; 115(2):184-193).

AT1Receptor Blockade Improves Myocardial Functional Performance in Obesity. / Bloqueio de Receptores AT1 Melhora o Desempenho Funcional Miocárdico na Obesidade.

Background Obesity has been associated with chronic activation of the renin-angiotensin-aldosterone system and with significant changes in cardiac performance. Objective To assess the impact of a blockade of angiotensin-II receptor type 1 (AT1receptor) on morphology and on myocardial functional performance in rats with high-fat diet- induced obesity. Methods Wistar rats (n=48) were submitted to control (2.9 kcal/g) or high-fat (3.6 kcal/g) diet for 20 weeks. After the 16thweek they were divided into four groups: Control (CO), Obese (OB), Control Losartan (CL) and Obese Losartan (OL). CL and OL received losartan (30 mg/kg/day) in drinking water for four weeks. Subsequently, body composition, systolic blood pressure (SBP) and echocardiographic variables were analyzed. Papillary muscle function was assessed at baseline with 2.50 mM calcium concentration ([Ca2+]o) and after inotropic maneuvers: post-pause potentiation (PPP), [Ca2+]oelevation, and during beta-adrenergic stimulation with isoproterenol. Analysis of the results was performed by the Two-Way ANOVA and by the appropriate comparison test. The level of significance was set at 5%. Results Although SBP change had been not maintained at the end of the experiment, obesity was associated with cardiac hypertrophy and with increased left ventricle posterior wall shortening velocity. In the study of papillary muscles in basal condition, CL showed lower developed tension maximum negative variation velocity (-dT/dt) than CO. The 60s PPP promoted lower -dT/dt and maximum developed tension (DT) in OB and CL compared with CO, and higher relative DT variation and maximum positive variation velocity (+dT/dt) in OL compared with CL and OB. Under 1.5, 2.0, and 2.5mM [Ca2+]o, the OL group showed higher -dT/dt than CL. Conclusion Losartan improves myocardial function in high-fat diet-induced obesity. (Arq Bras Cardiol. 2020;115(1):17-28).

Etiologia e fisiopatologia da fibromialgia / Etiology and pathophysiology of fibromyalgia

A fibromialgia é uma condição crônica de etiologia desconhecida e desvinculada de marcadores laboratoriais específicos para diagnóstico, devido à pobre caracterização da etiopatogenia. Em geral, as alterações comuns à fibromialgia também são observadas em outras condições de dor crônica, tornando a patogênese controversa entre diferentes condições patológicas. A etiologia desconhecida dificulta o diagnóstico e, consequentemente, repercute em um tratamento não tão eficaz de pacientes com fibromialgia. A restauração de desordens sistêmicas confere amplo espectro de possibilidades terapêuticas com potencial de orientar profissionais a estabelecer metas e métodos de avaliação. Diante disso, essa revisão narrativa se volta para debater hipóteses etiológicas e fisiopatológicas no desenvolvimento da fibromialgia.

Fibromyalgia is a chronic condition of unknown etiology unrelated to specific laboratory markers for diagnosis because of poor etiopathogenesis. In general, the changes common to fibromyalgia are also seen in other chronic pain conditions, making the pathogenesis controversial among different pathological conditions. The unknown etiology makes the diagnosis difficult and consequently has repercussions on a not so effective treatment of patients with fibromyalgia. The restoration of systemic disorders provides a wide spectrum of therapeutic possibilities with the potential to guide professionals in establishing goals and evaluation methods. Therefore, this narrative review discusses the etiological and pathophysiological hypotheses involved in the development of fibromyalgia.

Could current factors be associated with retrospective sports injuries in Brazilian jiu-jitsu? A cross-sectional study.

BACKGROUND: Brazilian jiu-jitsu is characterized by musculoskeletal disorders and high occurrence of sports injuries. The present study was aimed to analyze some internal factors, as well as to describe occurrence and characteristics of retrospective musculoskeletal injuries in different age groups of Brazilian jiu-jitsu practitioners. METHODS: One hundred ninety-three Brazilian jiu-jitsu practitioners, which were divided into three age groups: Adolescent, Adult, and Master. Besides anthropometric characterization, standard clinical tests were conducted to analyze the global and segmental joint flexibility, lumbar spine range of motion, and handgrip strength. Sports injury occurrence and total physical activity were obtained from an adapted morbidity survey and International Physical Activity Questionnaire - Short Form (IPAQ-SF), respectively. RESULTS: A total of 247 cases of retrospective injuries was registered (1.27 injury/ participant). Occurrence of rectus femoral muscle retraction in the right leg was increased within Master. Adult and Master have exhibited higher occurrence of sports injuries than Adolescent group (p < 0.05). Joint injuries were the most common sports-related injuries by all Brazilian jiu-jitsu practitioners. While female gender and exposure time constituted the most predictive variables for sports injury occurrence in Adolescent, graduation level was more associated with sports injuries occurrence in Adult. CONCLUSIONS: Joint injuries derived from combat demands were the main sports injury in all age categories of Brazilian jiu-jitsu. Master subjects presented a higher occurrence of clinical changes and retrospective musculoskeletal injuries in relation to other age groups. Female gender and exposure time constituted the main predictive factors in adolescent subjects, while graduation category was more directly associated with retrospective injury onset in the Adult group.

Analysis of high-intensity interval training on bone mineral density in an experimental model of type 2 diabetes

Purpose: To analyze the effect of high-intensity interval training (HIIT) on bone mineral density (BMD) in a model of type 2 diabetes mellitus. Methods: Thirty-two male, adult, 12-week-old rats (Rattus norvegicus), of the Wistar lineage, were used. The animals induced to the experimental model received a high fat diet for 10 days and, after that period, intraperitoneal injection of streptozotocin (40 mg·kg­1), dissolved in 20 mmol·L­1 sodium citrate solution (pH = 4.5). The experimental group of diabetes was formed by the animals that, 48 h after the injection of streptozotocin, had fasting blood glucose > 250 mg·dL­1). The animals were randomly divided into four groups with eight animals each: HIIT experimental diabetes; HIIT control; sedentary experimental diabetes and sedentary control. The animals in the HIIT group performed an aerobic exercise protocol on a treadmill inclined at an angle of 15° to the horizontal, with interspersed intensity. Five weekly sessions, lasting 49 min each, were held for 6 weeks. The analysis of cortical bone density (CBD) and BMD were performed by X-ray images using the In-Vivo Xtreme II/Bruker system. Results: For CBD and BMD, when comparing diabetes and control groups, a significant difference was seen between groups in relation to HIIT (p = 0.007). Animals submitted and not submitted to HIIT in the same group showed a significant difference between groups in relation to diabetes (p < 0.001). Conclusions: The HIIT experimental diabetes group had increased CBD and BMD in comparison with the sedentary experimental diabetes group.

Influência da reabilitação física sobre aspectos funcionais em indivíduos submetidos à artroplastia total de quadril: uma revisão sistemática / Influence of physical rehabilitation on functional aspects in individuals submitted to total hip arthroplasty: a systematic review

Resumo Objetivo: Avaliar, por meio de revisão sistemática, a influência do tratamento fisioterapêutico sobre a funcionalidade, amplitude de movimento articular e força muscular em pacientes submetidos à artroplastia total de quadril devido à osteoartrite. Métodos: A busca sistemática de ensaios clínicos randomizados e não randomizados foi conduzida utilizando os bancos de dados eletrônicos PubMed, Web of Science, PEDro, Cochrane, Clinical Trials e SciELO, com base nas estratégias de pesquisa recomendadas pelos itens de relatórios preferenciais para análises sistemáticas e metanálises (PRISMA). Resultados: Em geral, protocolos supervisionados por fisioterapeutas associados à realização de exercícios ativos da musculatura periarticular do quadril e de extensores de joelho têm propiciado importante prognóstico físico e funcional. Exercícios resistidos (dinâmicos e isométricos) de alta intensidade são mais eficazes para a funcionalidade. Para a força muscular e Amplitude de movimento (ADM), exercícios dinâmicos com 3 a 5 séries de 8 a 12 repetições com baixa e alta intensidade promoveram ganhos mais expressivos em relação a outras modalidades terapêuticas. Conclusões: As técnicas e os protocolos utilizados pela fisioterapia para o tratamento da ATQ são variados e possuem importante eficácia clínica comprovada na literatura.

Abstract Objective: by performing a systematic review, the present study aimed to evaluate the influence of physical rehabilitation on functionality, range of motion and musculoskeletal strength in patients submitted to total hip arthroplasty due to osteoarthritis. Methods: a systematic search for randomized and non-randomized controlled trials was conducted using the PubMed, Web of Science, PEDro, Cochrane, Clinical Trials and SciELO electronic databases, using the search strategies recommended by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Results: in general, protocols supervised by physiotherapists associated with performing active exercises of the hip periarticular muscles and knee extensors have provided effective functional prognosis. High intensity resistance exercises (dynamic and isometric) are more effective in improving functionality. Dynamic exercises with three to five sets of eight to twelve low and high intensity repetitions promoted more pronounced increases in muscle strength and range of motion than other therapeutic modalities. Conclusions: the techniques and protocols used for physical therapy treatment after THA are wide-ranging and their clinical efficacy is demonstrated in literature.

High-fat Diet Promotes Cardiac Remodeling in an Experimental Model of Obesity.

BACKGROUND: Although nutritional, metabolic and cardiovascular abnormalities are commonly seen in experimental studies of obesity, it is uncertain whether these effects result from the treatment or from body adiposity. OBJECTIVE: To evaluate the influence of treatment and body composition on metabolic and cardiovascular aspects in rats receiving high saturated fat diet. METHODS: Sixteen Wistar rats were used, distributed into two groups, the control (C) group, treated with isocaloric diet (2.93 kcal/g) and an obese (OB) group, treated with high-fat diet (3.64 kcal/g). The study period was 20 weeks. Analyses of nutritional behavior, body composition, glycemia, cholesterolemia, lipemia, systolic arterial pressure, echocardiography, and cardiac histology were performed. RESULTS: High-fat diet associates with manifestations of obesity, accompanied by changes in glycemia, cardiomyocyte hypertrophy, and myocardial interstitial fibrosis. After adjusting for adiposity, the metabolic effects were normalized, whereas differences in morphometric changes between groups were maintained. CONCLUSION: It was concluded that adiposity body composition has a stronger association with metabolic disturbances in obese rodents, whereas the high-fat dietary intervention is found to be more related to cardiac morphological changes in experimental models of diet-induced obesity.

Bloqueio de Receptores AT1 Melhora o Desempenho Funcional Miocárdico na Obesidade / AT1Receptor Blockade Improves Myocardial Functional Performance in Obesity

Resumo Fundamento A obesidade tem sido associada com ativação crônica do sistema renina-angiotensina-aldosterona e importantes alterações no desempenho cardíaco. Objetivo Avaliar a influência do bloqueio de receptores de angiotensina-II do tipo 1 (AT1) sobre a morfologia e desempenho cardíaco de ratos obesos por dieta Métodos Ratos Wistar (n=48) foram submetidos a dieta controle (2,9 kcal/g) ou hiperlipídica (3,6 kcal/g) durante 20 semanas. Após a 16ª semana, foram distribuídos em quatro grupos: Controle (CO), Obeso (OB), Controle Losartan (CL) e Obeso Losartan (OL). CL e OL receberam losartan (30 mg/kg/dia) na água durante quatro semanas. Posteriormente, foram analisadas composição corporal, pressão arterial sistólica (PAS) e ecocardiograma. A função de músculos papilares foi avaliada em situação basal com concentração de cálcio ([Ca2+]o) de 2,50 mM e após manobras inotrópicas: potencial pós-pausa (PPP), elevação da [Ca2+]o e durante estimulação beta-adrenérgica com isoproterenol. A análise dos resultados foi feita por meio de Two-Way ANOVA e teste de comparações apropriado. O nível de significância considerado foi de 5%. Resultados Embora a alteração da PAS não tenha se mantido ao final do experimento, a obesidade se associou com hipertrofia cardíaca e maior velocidade de encurtamento da parede posterior do ventrículo esquerdo.No estudo de músculos papilares em condição basal, CL mostrou menor velocidade máxima de variação negativa da tensão desenvolvida (-dT/dt) do que CO. O PPP de 60s promoveu menor -dT/dt e pico de tensão desenvolvida (TD) em OB e CL, comparados ao CO, e maior variação relativa de TD e velocidade máxima de variação positiva (+dT/dt) no OL em relação a CL e OB. Sob 1,5, 2,0 e 2,5mM de [Ca2+]o, o grupo OL exibiu maior -dT/dt do que CL. Conclusão Losartan melhora a função miocárdica de ratos com obesidade induzida por dieta. (Arq Bras Cardiol. 2020; 115(1):17-28)

Abstract Background Obesity has been associated with chronic activation of the renin-angiotensin-aldosterone system and with significant changes in cardiac performance. Objective To assess the impact of a blockade of angiotensin-II receptor type 1 (AT1receptor) on morphology and on myocardial functional performance in rats with high-fat diet- induced obesity. Methods Wistar rats (n=48) were submitted to control (2.9 kcal/g) or high-fat (3.6 kcal/g) diet for 20 weeks. After the 16thweek they were divided into four groups: Control (CO), Obese (OB), Control Losartan (CL) and Obese Losartan (OL). CL and OL received losartan (30 mg/kg/day) in drinking water for four weeks. Subsequently, body composition, systolic blood pressure (SBP) and echocardiographic variables were analyzed. Papillary muscle function was assessed at baseline with 2.50 mM calcium concentration ([Ca2+]o) and after inotropic maneuvers: post-pause potentiation (PPP), [Ca2+]oelevation, and during beta-adrenergic stimulation with isoproterenol. Analysis of the results was performed by the Two-Way ANOVA and by the appropriate comparison test. The level of significance was set at 5%. Results Although SBP change had been not maintained at the end of the experiment, obesity was associated with cardiac hypertrophy and with increased left ventricle posterior wall shortening velocity. In the study of papillary muscles in basal condition, CL showed lower developed tension maximum negative variation velocity (-dT/dt) than CO. The 60s PPP promoted lower -dT/dt and maximum developed tension (DT) in OB and CL compared with CO, and higher relative DT variation and maximum positive variation velocity (+dT/dt) in OL compared with CL and OB. Under 1.5, 2.0, and 2.5mM [Ca2+]o, the OL group showed higher -dT/dt than CL. Conclusion Losartan improves myocardial function in high-fat diet-induced obesity. (Arq Bras Cardiol. 2020;115(1):17-28)

Dieta Intermitente Atenua a Remodelação Cardíaca Causada pelo Exercício Físico / Intermittent Fasting Attenuates Exercise Training-Induced Cardiac Remodeling

Resumo Fundamento A influência de intervenções não farmacológicas como restrição calórica e exercício físico sobre a saúde e prevenção de enfermidades cardíacas tem sido documentada em estudos clínicos e experimentais. Objetivo Analisar a influência da combinação entre dieta intermitente e exercício físico sobre a capacidade funcional, metabolismo glicêmico e remodelação cardíaca. Métodos Foram utilizados 60 ratos Wistar machos distribuídos em quatro grupos: Controle (C), Exercício Físico (EF), Dieta Intermitente (DI) e Exercício Físico e Dieta Intermitente (EDI). Durante 12 semanas, enquanto C e EF foram tratados diariamente com dieta comercial padrão ad libitum, DI e EDI receberam dieta similar em dias alternados com dias de jejum. Os grupos EF e EDI foram submetidos a protocolo de corrida em esteira rolante. Posteriormente, foram analisadas capacidade funcional, comportamento nutricional e metabolismo glicêmico. Além da morfologia do coração, a expressão proteica das proteínas extracellular signal-regulated kinase (ERK) e c-Jun N-terminal kinase (JNK) no coração foi avaliada por Western-blot. A análise dos resultados foi feita por meio de Two-Way ANOVA e teste de Student-Newman-Keuls. O nível de significância considerado foi de 5%. Resultados O exercício físico aumentou a capacidade funcional nos grupos EF e EDI, e acarretou fibrose cardíaca. A combinação entre dieta intermitente e exercício físico resultou em menor área sob a curva de glicemia e menores medidas de área e interstício cardíaco no EDI em relação ao EF. A expressão de proteínas ERK e JNK foi similar entre os grupos (p>0,05). Conclusões Dieta intermitente se associa com melhor tolerância glicêmica e atenua o processo de remodelação cardíaca decorrente do exercício físico. (Arq Bras Cardiol. 2020; 115(2):184-193)

Abstract Background The effects of non-pharmacological interventions such as calorie restriction and exercise training on health and prevention of cardiovascular diseases have been investigated in clinical and experimental studies. Objective To analyze the influence of intermittent fasting and exercise training on functional fitness, glycemia and cardiac remodeling. Methods Wistar rats (n=60) were randomly divided into four groups: control, exercise training (ET), intermittent fasting (IF) and exercise training plus intermittent fasting (ETI). Over 12 weeks, control and ET animals were fed daily a standard commercial diet ad libitum , while IF and ETI animals were fed every other day. In addition, the ET and ETI groups were submitted to a running protocol on a treadmill. After this period, functional fitness, nutritional parameters and blood glucose levels were analyzed. In addition to heart morphology, myocardial protein expression of extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) was assessed by Western-blot. The results were analyzed using two-way ANOVA and Student-Newman-Keuls test. The level of significance considered was 5%. Results Exercise training increased functional fitness in the ET and ETI groups and promoted cardiac fibrosis. The combination of intermittent fasting and exercise training resulted in a smaller area under the blood glucose curve and reduced cardiomyocyte cross-sectional area and interstitial collagen fraction in the ETI group compared to ET. ERK and JNK expression levels were similar among groups (p>0.05). Conclusions Intermittent fasting is associated with improved glucose tolerance and attenuates cardiac remodeling induced by exercise training (Arq Bras Cardiol. 2020; 115(2):184-193)

Obesity preserves myocardial function during blockade of the glycolytic pathway.

BACKGROUND: Obesity is defined by excessive accumulation of body fat relative to lean tissue. Studies during the last few years indicate that cardiac function in obese animals may be preserved, increased or diminished. OBJECTIVE: Study the energy balance of the myocardium with the hypothesis that the increase in fatty acid oxidation and reduced glucose leads to cardiac dysfunction in obesity. METHODS: 30-day-old male Wistar rats were fed standard and hypercaloric diet for 30 weeks. Cardiac function and morphology were assessed. In this paper was viewed the general characteristics and comorbities associated to obesity. The structure cardiac was determined by weights of the heart and left ventricle (LV). Myocardial function was evaluated by studying isolated papillary muscles from the LV, under the baseline condition and after inotropic and lusitropic maneuvers: myocardial stiffness; postrest contraction; increase in extracellular Ca2+ concentration; change in heart rate and inhibitor of glycolytic pathway. RESULTS: Compared with control group, the obese rats had increased body fat and co-morbities associated with obesity. Functional assessment after blocking iodoacetate shows no difference in the linear regression of DT, however, the RT showed a statistically significant difference in behavior between the control and the obese group, most notable being the slope in group C. CONCLUSION: The energy imbalance on obesity did not cause cardiac dysfunction. On the contrary, the prioritization of fatty acids utilization provides protection to cardiac muscle during the inhibition of glycolysis, suggesting that this pathway is fewer used by obese cardiac muscle.

Cardiovascular effects of a strength test (1rm) in prehypertensive subjects / Efeitos cardiovasculares de um teste de força (1rm) em sujeitos pré-hipertensos / Efectos cardiovasculares de un test de fuerza (1rm) en sujetos pre-hipertensos

ABSTRACT Introduction: Physical exercise promotes positive physiological adaptations, reducing the risk of developing cardiovascular diseases and promoting greater autonomic control of heart rate and reduction in pressure levels. Objective: To compare the behavior of arterial pressure and autonomic heart rate modulation in the 1-repetition maximum knee extension test, performed on the 45-degree leg press machine in normotensive and prehypertensive subjects. Methods: Twenty-four male volunteers were assessed. Blood pressure (BP) and heart rate variability (HRV) were evaluated at rest, immediately after the maximum load achieved and during the 10, 20, 30 and 40-minute recovery phases. Statistical analyses were obtained using SigmaStat 3.5 software and a level of significance of 5%. Results: Mean and standard deviation were used to identify 12 normotensive patients (N) aged = 25.5 ± 5.7 years; height = 174.3 ± 6.6 cm; BMI = 24.9 ± 2.4; SBP on average = 112.6 ± 5.6 mmHg and 12 prehypertensive (PH) patients aged = 29.8 ± 6.5 years; height = 175.7 ± 6.7 cm; BMI = 27.8 ± 6.5; mean SBP = 131.1 ± 3.2 mmHg. There was a statistical difference in the pNN50 index (%) at rest (PH = 1.13 ± 0.66 and N = 1.58 ± 0.35) and in the LF/HF index, also at rest (PH = 0.18 ± 0.29 and N = −0.18 ± 0.36). Conclusion: The one-repetition maximum (1RM) test did not promote cardiovascular risk in the prehypertensive group during its execution, with double product results lower than 30,000 mmHg.bpm, demonstrating lower cardiac overload. Moreover, HRV exhibited similarity in sympathetic-vagal behavior, in the time/frequency domain, between the groups. Level of Evidence III; Study Case-control.

RESUMO Introdução: O exercício físico promove adaptações fisiológicas de caráter positivo, diminuindo os riscos de desenvolvimento de doenças cardiovasculares, além de promover um maior controle autonômico da frequência cardíaca e redução nos níveis pressóricos. Objetivo: Comparar o comportamento da pressão arterial e da modulação autonômica da frequência cardíaca no teste de uma repetição máxima de extensão de joelhos, realizado no aparelho de Leg press 45° em sujeitos normotensos e pré-hipertensos. Métodos: Foram avaliados 24 voluntários do sexo masculino. Foi feita a avaliação da pressão arterial (PA) e da variabilidade da frequência cardíaca (VFC) no momento de repouso, imediatamente após a carga máxima alcançada e durante as fases de 10, 20, 30 e 40 minutos de recuperação. As análises estatísticas foram obtidas através do software SigmaStat 3.5 e nível de significância igual a 5%. Resultados: A média e o desvio padrão foram utilizados para identificação de 12 normotensos (N) com idade = 25,5 ± 5,7 anos; altura = 174,3 ± 6,6 cm; IMC = 24,9 ± 2,4; PAS em média = 112,6 ± 5,6 mmHg e 12 pré-hipertensos (PH) com idade = 29,8 ± 6,5 anos; altura = 175,7 ± 6,7 cm; IMC = 27,8 ± 6,5; PAS em média = 131,1 ± 3,2 mmHg. Houve diferença estatística no índice pNN50 (%) no momento repouso (PH = 1,13 ± 0,66 e N =1,58 ± 0,35) e no índice LF/HF igualmente no momento repouso (PH = 0,18 ± 0,29 e N = −0,18 ± 0,36). Conclusão: O teste de uma repetição máxima (1RM) não promoveu risco cardiovascular no grupo pré-hipertenso durante sua execução, com resultados de duplo produto menor que 30.000 mmHg.bpm, demonstrando menor sobrecarga cardíaca, e a VFC apresentou similaridade no comportamento simpático-vagal no domínio do tempo e frequência entre os grupos. Nível de evidência III; Estudo Caso controle.

RESUMEN Introducción: El ejercicio físico promueve adaptaciones fisiológicas de carácter positivo, disminuyendo los riesgos de desarrollo de enfermedades cardiovasculares, además de promover un mayor control autonómico de la frecuencia cardíaca y reducción en los niveles presóricos. Objetivo: Comparar el comportamiento de la presión arterial y de la modulación autonómica de la frecuencia cardíaca en el test de una repetición máxima de extensión de rodillas, realizado en el aparato de Leg press 45° en sujetos normotensos y pre-hipertensos. Métodos: Fueron evaluados 24 voluntarios del sexo masculino. Fue hecha la evaluación de la presión arterial (PA) y de la variabilidad de la frecuencia cardíaca (VFC) en el momento de reposo, inmediatamente después de la carga máxima alcanzada y durante las fases de 10, 20, 30 y 40 minutos de recuperación. Los análisis estadísticos fueron obtenidos a través del software SigmaStat 3.5 y nivel de significancia igual a 5%. Resultados: El promedio y la desviación estándar fueron utilizados para identificación de 12 normotensos (N) con edad = 25,5 ± 5,7 años; altura = 174,3 ± 6,6 cm; IMC = 24,9 ± 2,4; PAS en promedio = 112,6 ± 5,6 mmHg y 12 pre-hipertensos (PH) con edad = 29,8 ± 6,5 años; altura = 175,7 ± 6,7 cm; IMC = 27,8 ± 6,5; PAS en promedio = 131,1 ± 3,2 mmHg. Hubo diferencia estadística en el índice pNN50 (%) en el momento reposo (PH = 1,13 ± 0,66 y N =1,58 ± 0,35) y en el índice LF/HF igualmente en el momento reposo (PH = 0,18 ± 0,29 y N = −0,18 ± 0,36). Conclusión: El test de una repetición máxima (1RM) no promovió riesgo cardiovascular en el grupo pre-hipertenso durante su ejecución, con resultados de doble producto menor que 30.000 mmHg.bpm, demostrando menor sobrecarga cardíaca, y la VFC presentó similitud en el comportamiento simpático-vagal en el dominio del tiempo y frecuencia entre los grupos. Nivel de evidencia III; Estudio Caso control.

Influence of term of exposure to high-fat diet-induced obesity on myocardial collagen type I and III.

BACKGROUND: Obesity is a risk factor for many medical complications; medical research has shown that hemodynamic, morphological and functional abnormalities are correlated with the duration and severity of obesity. OBJECTIVE: Present study determined the influence of term of exposure to high-fat diet-induced obesity on myocardial collagen type I and III. METHODS: Thirty-day-old male Wistar rats were randomly distributed into two groups: a control (C) group fed a standard rat chow and an obese (Ob) group alternately fed one of four palatable high-fat diets. Each diet was changed daily, and the rats were maintained on their respective diets for 15 (C15 and Ob15) and 30 (C30 and Ob30) consecutive weeks. Obesity was determined by adiposity index. RESULTS: The Ob15 group was similar to the C15 group regarding the expression of myocardial collagen type I; however, expression in the Ob30 group was less than C30 group. The time of exposure to obesity was associated with a reduction in collagen type I in Ob30 when compared with Ob15. Obesity did not affect collagen type III expression. CONCLUSION: This study showed that the time of exposure to obesity for 30 weeks induced by unsaturated high-fat diet caused a reduction in myocardial collagen type I expression in the obese rats. However, no effect was seen on myocardial collagen type III expression.